Zero-Scale Platform

A lightweight, high-density serverless execution runtime and dynamic reverse-proxy for Kubernetes.

Rather than maintaining dedicated Pods and container runtimes for infrequently accessed services, the Zero-Scale Platform multiplexes stateless and microservice binaries inside a single sandboxed container using transient systemd-run execution units.

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How It Works

graph TD
    Client[HTTP Client] -->|1. Incoming Request :80| Ingress[Kubernetes Ingress]
    Ingress -->|2. Route Host Header| Gateway[Gateway Reverse Proxy]
    
    subgraph "Zero-Scale Gateway Pod (systemd-runner)"
        Gateway -->|3. Check /opt/apps/<host>| Volume[(Longhorn Binaries Volume)]
        Gateway -->|4. Fetch DB Secret & ConfigMap| K8sAPI[Kubernetes InCluster API]
        Gateway -->|5. systemd-run with dynamic PORT & DB env| Systemd[systemd PID 1]
        Systemd -->|6. Spawns sandboxed transient service| App[Dynamic App Process]
        Gateway -->|7. Reverse Proxy to 127.0.0.1:PORT| App
        Reaper[Idle Reaper Timer] -->|8. Idle > 15m: systemctl stop| App
    end

Core Features

1. True Scale-to-Zero: Idle apps consume zero memory and zero CPU.
2. Sub-Second Cold Starts: Because apps launch as local native Linux processes via systemd-run, cold starts complete in ~500 ms (warm requests respond in ~50–80 ms).
3. Dynamic Credential Injection: Automatically reads Kubernetes ConfigMap and Secret resources to pass database credentials (DATABASE_HOST, DATABASE_USER, DATABASE_PASSWORD, etc.) to the binary on startup.
4. Storage Integration: Seamlessly bind-mounts Longhorn shared RWX volumes (e.g. /app/uploads) into the sandboxed process.
5. Automated Idle Reaper: Monitors application activity; after 15 minutes of inactivity, the gateway terminates the process and reclaims the ephemeral port.

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Directory Structure

zero-scale-platform/
├── Makefile                      # Standardized build, image, and deploy commands
├── go.mod                        # Go module definition
├── Dockerfile.systemd            # Container image (Debian Bookworm + systemd + wasmtime)
├── cmd/
│   ├── gateway/
│   │   └── main.go               # The core zero-scale proxy daemon
│   └── mock-app/
│       └── main.go               # Reference mock HTTP service
├── deploy/                       # Kubernetes manifests
│   ├── deployment.yaml           # Gateway Deployment (replaces manual pods)
│   ├── service.yaml              # Gateway ClusterIP Service (:80)
│   └── ingress.yaml              # Ingress routing configuration
├── scripts/
│   └── zero-scale-ctl.sh         # CLI tool for deploying and monitoring apps
└── services/                     # Systemd service unit templates
    ├── gateway.service
    └── ...

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Management CLI (zero-scale-ctl.sh)

The helper script in scripts/zero-scale-ctl.sh simplifies managing zero-scale applications:

Deploy an Application

./scripts/zero-scale-ctl.sh deploy-app \
  --name bdash2 \
  --host bdash2.kube.fairfaxmedia.net \
  --url http://minio.minio-operator/binaries/bdash-x86_64 \
  --db \
  --mount /app/uploads

List Configured Applications

./scripts/zero-scale-ctl.sh list-apps

Check Application Status & Logs

# Check systemd status inside the gateway
./scripts/zero-scale-ctl.sh status bdash2.kube.fairfaxmedia.net

# Tail systemd journal logs
./scripts/zero-scale-ctl.sh logs bdash2.kube.fairfaxmedia.net

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Building and Deploying

1. Compile Binaries

make build

2. Build and Push Container Image

make image
make push

3. Deploy to Kubernetes

make deploy